Tropical malaria caused by the protozoon Plasmodium falciparum is responsible for ca. 515 million clinical episodes and almost 3 million human deaths annually. Parasite resistance to the presently available drugs like chloroquine increases continuously. Currently there is only one class of drugs, the artemisinin derivatives, for which resistance has not yet been observed in the field. To further understand the mechanisms of resistance development and the biochemical pathways involved, differential multi- dimensional proteome analysis represents a most valuable tool. Within the framework of this American- German collaboration we aim at studying the proteomic changes induced in blood stage trophozoites of the malarial parasite Plasmodium falciparum after exposure to chloroquine or artemisinin. The project has two specific aims: 1) Development and validation of the use of stable isotope labeling by amino acids in cell culture (SILAC) in order to quantify protein expression in complex mixtures of Plasmodium falciparum blood stages treated with two different types of antimalarial drugs using Multidimensional Protein Identification Technology (MudPIT). Sample preparation as well as fractionation of the samples will be optimized. 2) Identification of proteins and pathways that are affected by the two types of drugs. On the basis of the expected results we hope to learn about the metabolic pathways specifically induced by the drugs as well as mechanisms of resistance and potential novel drug targets. Particular emphasis will be given to redox related defense and signaling pathways. [unreadable] [unreadable] [unreadable]